Uncommonly Cool: The Snowbell Trees (Styrax)
Snowbell trees (Styrax) are rare but remarkable with stunning blooms, sweet fragrance, unique galls, and useful resin. Discover why they’re uncommonly cool.
Plant specimen by Peter FritschBRIT Collections
Most plant species are not well known to people—only a small fraction are commonly grown in botanic gardens. This is also true of the snowbell trees (genus Styrax).
But when people take the time to notice snowbell flowers, like the ones on this Japanese species Styrax obassia, they marvel at their beauty and want to know more about them!
Mediterranean snowbell
Snowbell trees are native to eastern Asia and the Americas in north temperate and tropical areas. The one exception is shown here, the Mediterranean snowbell (Styrax officinalis).
Originally this plant was thought to produce a resin called storax, but now it's thought that this is a mix up with resin produced by the Sweetgum tree (Liquidambar), shown here.
Although Mediterranean snowbell is not likely a resin-source, there IS a valuable resin called benzoin that is harvested from Styrax benzoin, a species native to Southeast Asia.
Plant specimen (2011-01-12) by Wibowo DjatmikoOriginal Source: Wikipedia
Benzoin resin is used in the confection industry as a flavoring agent and in the pharmaceutical industry as an emulsifier. It is also used commonly in incense.
Plant specimen (2016-03-31) by D.L. Kelly, F. Fernandez, S. Hanley, P. O'Brien, C. OwensBRIT Collections
A new Honduran snowbell
There are currently about 140 species of snowbells, with new species still being described. One new snowbell species is Styrax paulhousei, a small tree known from a single mountain in Honduras.
Plant specimen (2005-12-16) by P. Thomas, Koun Theah, Thon Sokhon, Seth Teng, Srun Sokhon, Yan BounsoeungBRIT Collections
...and also one from Cambodia!
Styrax cambodianus was found along the Ho-Chi Minh Trail in Cambodia. These preserved specimens are known as “types” and serve to establish the name for the species.
Plant specimen (2005-12-16/2016-03-01) by Sr. F. Fernandez and Philip ThomasBRIT Collections
In real life they look like this. On the left is the Honduran species. On the right, the Cambodian species.
Snowbell flowers live up to their descriptive name—creamy white petals and a bell-like shape, as in this Styrax confusus.
Japanese snowbell
Styrax species have a wonderful fragrance similar to orange blossoms. Sometimes thousands of flowers can be produced by a single plant, as in this Japanese snowbell (Styrax japonicus).
Stellate trichomes...
An interesting feature of these plants is the “hairs” or trichomes that cover their leaf surfaces. The hairs are “stellate,” or star-shaped.
...or scales
And sometimes the hairs fuse together into beautiful scales.
Plant specimen (2000-06-01/2000-06-30) by Peter FritschBRIT Collections
Gall-y gee whiz!
A unique feature of the Asian species is the presence of large and variously shaped galls produced by a group of aphids whose reproductive phase occurs only on species of Styrax. This is a cauliform gall.
Plant specimen (1990-01-01/1999-12-31) by S. Aoki, Rissho University, JapanBRIT Collections
Egg-bearing female aphids fight it out to claim their own leaf bud. They then lay their eggs in the gall they form, which vary in shape according to the type of aphid, the species of Styrax, and the plant tissue from which the gall forms. These are called pinwheel galls.
Plant specimen by Peter FritschBRIT Collections
The snowbells may be uncommon, but with beautiful flowers, crazy galls, amazing fragrance, useful resin, and diverse habitats, we think they're uncommonly cool!
Follow the Botanical Research Institute of Texas for more fascinating research on Styrax!
Fritsch, PW, P Thomas & V Ly. 2020. A new species of Styrax series Cyrta (Styracaceae) from Cambodia. Journal of the Botanical Research Institute of Texas 14(2):343-347. https://doi.org/10.17348/jbrit.v14.i2.1011
Fritsch, PW, C Whitefoord & DL Kelly. 2018. Styrax paulhousei (Styracaceae), a new species from Honduras. Journal of the Botanical Research Institute of Texas 12(2):499-505. Retrieved from https://journals.brit.org/jbrit/article/view/952
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